JP6354139B2 - Electronic device, method for manufacturing electronic device, electronic apparatus, and moving body - Google Patents

Description

  The present invention relates to an electronic device, an electronic device manufacturing method, an electronic apparatus, and a moving object.

2. Description of the Related Art Conventionally, an electronic device including a sealing portion that seals a space (cavity) in which a functional element is mounted as a sensor that detects a physical quantity such as angular velocity and acceleration is known. In general, such a cavity is sealed in a state where the inside of the cavity is decompressed or replaced with an inert gas or the like. The cavity is sealed by providing a hole penetrating the cavity, disposing a sealing member in the hole, irradiating the sealing member with laser light to melt it, and closing the hole.
For example, in Patent Document 1, a metal serving as a sealing member is disposed in a hole penetrating from a cavity to the outside, and the sealing member is melted by irradiating the sealing member with a laser beam, thereby closing the hole and forming a cavity. An electronic device having a structure in which a tee is sealed is disclosed.

Japanese Patent No. 4113062

  However, the above-described electronic device has a problem in that members other than the sealing member generate heat due to the laser beam irradiated to melt the sealing member, and the gas released by the heat generation of the member is released into the cavity. It was. When these gases are released into the cavity, the pressure in the cavity and the gas composition in the cavity may change, which may affect the operating characteristics of the mounted functional elements. .

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The manufacturing method of an electronic device according to this application example includes a base material, a cavity surrounded by the base material, and a sealing portion provided in the base material and disposed in a hole that penetrates the cavity And a functional element provided in the cavity, wherein the sealing member disposed in the hole is irradiated with laser light to melt and seal the sealing member. Including a step of forming a stop, and the spot width of the laser beam is narrower than the width of the sealing member when the hole is viewed in plan.

  According to such an electronic device manufacturing method, the laser beam is irradiated to the sealing member other than the sealing member because the spot width of the laser beam irradiated to the sealing member that closes the hole is narrower than the width of the sealing member. It can be suppressed. Therefore, since the laser beam is suppressed from irradiating the base material and the holes provided in the base material, the heat generated from the base material and the gas contained in the base material with the heat generation are separated and the Release into the tee can be suppressed. Therefore, it is possible to suppress changes in the pressure and gas composition in the cavity, and to influence the operation of the functional element provided in the cavity.

[Application Example 2]
In the method for manufacturing an electronic device according to the application example, the base material includes a first base material and a second base material provided with a hole, and the step of melting the sealing member includes the second base material. It is preferable to close the hole by melting the sealing member while heating the material.

  According to such a method for manufacturing an electronic device, the inner wall of the hole portion in contact with the sealing member can be heated by heating the second base material provided with the hole portion. Therefore, the sealing member melted by the irradiation with the laser light is deprived of heat by the inner wall of the hole, and solidification on the inner wall surface and surface tension on the inner wall surface can be suppressed. Therefore, the hole can be closed with a uniform thickness of the sealing member, and the cavity can be sealed.

[Application Example 3]
In the electronic device manufacturing method according to the application example described above, the hole has a first opening having an opening on the cavity side and a second opening having an opening on the opposite side of the cavity. Then, when the hole is viewed in plan, the hole can be closed by irradiating the sealing member with a laser beam wider than the width of the first opening and narrower than the width of the second opening to melt the sealing member. preferable.

  According to such a method for manufacturing an electronic device, the sealing member that is wider than the first opening that opens in the cavity is disposed in the hole, so that the sealing member before melting enters the cavity. Can be suppressed and the sealing effect of the cavity can be enhanced. Moreover, it can suppress that the laser beam which fuses a sealing member is irradiated to parts other than a sealing member by arrange | positioning the sealing member narrower than a 2nd opening in a hole. Therefore, the laser beam is suppressed from irradiating the base material and the holes provided in the base material. Therefore, the heat generation of the base material and the gas contained in the base material with the heat generation are separated and the Release into the tee can be suppressed. Therefore, the airtightness of the cavity can be increased, the pressure in the cavity and the change of the gas composition can be suppressed, and the influence on the operation of the functional element provided in the cavity can be suppressed.

[Application Example 4]
In the electronic device manufacturing method according to the application example described above, it is preferable to include a step of decompressing the cavity before the step of melting the sealing member.

  According to such a method for manufacturing an electronic device, gas and moisture in the cavity can be removed by performing a step of decompressing the inside of the cavity prior to the step of melting the sealing member.

[Application Example 5]
The electronic device according to this application example is provided so as to close the hole, the base material, the cavity surrounded by the base material, the hole provided in the base material and penetrating the cavity. And a functional element provided in the cavity, and the sealing portion has a spot width narrower than the width of the sealing member forming the sealing portion when the hole portion is viewed in plan It is melted by a laser beam having

  According to such an electronic device, the laser beam is irradiated other than the sealing member because the spot width of the laser beam irradiated to the sealing member closing the hole is narrower than the width of the sealing member. Can be suppressed. Therefore, since the laser beam is suppressed from irradiating the base material and the holes provided in the base material, the heat generated from the base material and the gas contained in the base material with the heat generation are separated and the Release into the tee can be suppressed. Therefore, it is possible to suppress changes in the pressure and gas composition in the cavity, and to influence the operation of the functional element provided in the cavity.

[Application Example 6]
In the electronic device according to the application example described above, it is preferable that the base material includes a first base material and a second base material, and a hole is provided in the second base material.

  According to such an electronic device, since the base material surrounding the cavity is composed of the first base material and the second base material, the functional element can be easily disposed in the cavity. Moreover, since the hole part is provided in the 2nd base material, a hole part can be provided easily.

[Application Example 7]
In the electronic device according to the application example, it is preferable that the second base material is made of a material containing silicon.

  According to such an electronic device, since the second substrate is made of a material containing silicon, the adhesion between the hole provided in the second substrate and the sealing portion that closes the hole is improved. be able to. Therefore, the airtightness of the sealed cavity can be improved. Therefore, it is possible to realize an electronic device that suppresses the pressure change in the cavity and suppresses the influence on the operation of the functional element provided in the cavity.

[Application Example 8]
In the electronic device according to the application example, it is preferable that a metal film is provided on the inner wall of the hole.

  According to such an electronic device, since the metal film is provided on the inner wall of the hole, it is possible to further improve the adhesion with the sealing part that closes the hole. Therefore, the airtightness of the sealed cavity can be improved. Therefore, it is possible to realize an electronic device that suppresses the pressure change in the cavity and suppresses the influence on the operation of the functional element provided in the cavity.

[Application Example 9]
An electronic apparatus according to this application example is characterized in that the above-described electronic device is mounted.

  According to such an electronic device, a highly reliable electronic device can be obtained by mounting the above-described electronic device.

[Application Example 10]
The moving body according to this application example is characterized in that the electronic device described above is mounted.

  According to such a moving body, a highly reliable moving body can be obtained by mounting the electronic device described above.

FIG. 3 is a cross-sectional view schematically showing the electronic device according to the embodiment. The top view which shows an electronic device typically. The top view which shows typically the functional element which comprises an electronic device. FIG. 14 illustrates operation of an electronic device. FIG. 14 illustrates operation of an electronic device. FIG. 14 illustrates operation of an electronic device. FIG. 14 illustrates operation of an electronic device. The figure explaining the manufacturing method of the electronic device which concerns on this embodiment. The figure explaining the manufacturing method of an electronic device. The figure explaining the manufacturing method of an electronic device. Sectional drawing which expands and shows each sealing part, performing the comparative experiment of the electronic device of this embodiment, and the electronic device in a prior art example. The graph which compared the resonance characteristic Q value of the electronic device of this embodiment, and the electronic device in a prior art example. FIG. 10 is a diagram schematically illustrating an electronic apparatus according to an example. FIG. 10 is a diagram schematically illustrating an electronic apparatus according to an example. FIG. 10 is a diagram schematically illustrating an electronic apparatus according to an example. The figure which shows the mobile body which concerns on an Example typically.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure shown below, the size and ratio of each component may be described differently from the actual component in order to make each component large enough to be recognized on the drawing. is there.

[Embodiment]
The electronic device according to the embodiment and the method for manufacturing the electronic device will be described with reference to FIGS. 1 to 12 as an example of an aspect in which a functional element for detecting angular velocity or the like is mounted.
FIG. 1 is a cross-sectional view schematically showing the electronic device of the present embodiment. FIG. 2 is a plan view of the electronic device viewed from the second base material side. FIG. 3 is a plan view showing a structure of a functional element mounted on the electronic device. 4 to 7 are explanatory diagrams for explaining the operation of the functional element. 8 to 10 are process diagrams illustrating the manufacturing process of the electronic device of this embodiment. FIG. 11 is an enlarged cross-sectional view showing the respective sealing portions by conducting a comparative experiment between the electronic device of the present embodiment and the electronic device in the conventional example. FIG. 12 is a graph comparing resonance characteristic Q values of the electronic device of this embodiment and the electronic device in the conventional example. 1 to 9, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other, and the Z axis is an axis that indicates a direction in which gravity acts in a direction orthogonal to the X axis and the Y axis. is there.

(Structure of electronic device 1)
As shown in FIG. 1, the electronic device 1 of the present embodiment is provided with a first base material 10, a second base material 20, and a functional element 100. In the electronic device 1, the functional element 100 is disposed between the first base material 10 and the second base material 20. By making the cavity 32 a space generated when the first base material 10 and the second base material 20 face each other, the functional element 100 can be vibrated.
For convenience, in FIG. 1, FIG. 2, FIG. 8, and FIG. 9, the functional element 100 is illustrated in a simplified manner. Moreover, in FIG. 2, illustration of the sealing part 60 is abbreviate | omitted.

(First base material 10)
The first base material 10 is a base material on which the functional element 100 is supported. The first base material 10 is provided with a recess 12. A functional element 100 is connected to the first base material 10. The first substrate 10 and the functional element 100 are connected by connecting the top surface 12a of the recess 12 and the outer peripheral edge 103 of the functional element 100.
As will be described later, the functional element 100 is accompanied by a constant vibration operation in order to detect angular velocity and the like. Since the outer peripheral edge 103 is connected to the top surface 12 a of the recess 12, the functional element 100 can perform a desired vibration operation without being interfered with the first base material 10.

As the material of the first base material 10, for example, a base material containing glass, silicon, and quartz can be used. In the electronic device 1 of the present embodiment, the first substrate 10 uses a glass substrate containing borosilicate glass. When borosilicate glass is used for the first substrate 10, the recess 12 can be easily formed by a wet etching method such as hydrofluoric acid. Further, the bonding with the functional element 100 can be performed firmly by the anodic bonding method. In addition, the material which comprises the 1st base material 10 is not specifically limited, You may change suitably if the formation of the recessed part 12 is possible and the joining performance with the 2nd base material 20 is favorable. .
A metal plate 11 is provided on the top surface 12 a of the first base material 10. The metal plate 11 is provided on the main surface 10a that overlaps at least a hole 40 described later when the first base material 10 is viewed in a plan view from the direction intersecting the main surface 10a to which the second base material 20 is joined. Yes.

(Second base material 20)
The second base material 20 is connected to the first base material 10 so as to cover the functional element 100. The second base material 20 is a so-called lid member.
The second base material 20 is provided with a concave portion 22 having a concave shape that covers the functional element 100. The concave portion 22 is provided on the main surface 20 a of the second base material 20 on the side facing the first base material 10. The second base material 20 is connected so that the top surface 12 a of the recess 12 in the first base material 10 and the top surface 22 a of the recess 22 in the second base material 20 face each other.
By connecting the first base material 10 and the second base material 20, a space formed by the concave portion 12 and the concave portion 22 facing each other can be used as the cavity 32 in which the functional element 100 is accommodated.

The second base material 20 is provided with a hole 40 that penetrates the main surface 20a and the sub surface 20b that is the opposite surface. The hole 40 has a first opening 41 that opens to the main surface 20a side, and a second opening 42 that opens to the sub surface 20b side. The hole portion 40 is provided as a sealing port for sealing the atmosphere of the cavity 32, and a sealing portion 60 described later is disposed. The shape of the hole 40 is not particularly limited, but when the hole 40 is viewed in plan, the width of the first opening 41 on the main surface 20a side is narrower than the second opening 42 on the sub surface 20b side. Is preferred. This is because the sealing member 60 </ b> B can be easily disposed when the second base material 20 is on the upper surface. In this embodiment, in order to arrange the sealing member 60B having a diameter of 250 μm, the first opening 41 is set to 100 μm or less, and the second opening 42 is set to 300 μm or more.
Furthermore, the hole 40 can have a pyramid shape as shown in FIG. At this time, for example, a spherical member can be arranged as the sealing member 60B. By disposing the spherical sealing member 60B in the pyramidal hole, a gap can be left between the hole and the sealing member. Due to the presence of the air gap, the residual gas in the cavity 32 can be efficiently extracted at the time of decompression described later. The hole 40 having a pyramid shape has a curved surface on its side 40e. Since the side 40e is provided with a curved surface, generation of cracks can be suppressed when a sealing member 60B described later is melted. Alternatively, the hole can have a conical shape as shown in FIG. At this time, as the sealing member 60B, for example, a cube or a rectangular parallelepiped can be arranged.

The second base material 20 is provided with a metal film 50 on the sub surface 20b side.
The metal film 50 is extended from the inner wall 40 a of the hole 40 to the sub surface 20 b side of the second base material 20. As the metal film 50, it is preferable to use titanium (Ti) for the base layer and gold (Au) for the surface layer. The metal film 50 improves the wettability of a sealing member 60B, which will be described later, by using gold (Au) for the surface layer, and uses the titanium (Ti) for the base layer to seal the sealing member 60B and the hole 40 (inner wall 40a). ) Can be improved. In addition to titanium, the underlayer may be chromium (Cr) or tungsten (W).
In addition, the material which comprises the metal film 50 is not specifically limited, You may change suitably with the material which comprises the 2nd base material 20 and the sealing part 60. FIG.

  As the second base material 20, for example, a base material containing glass, silicon, and quartz can be used. In the electronic device 1 of the present embodiment, the second base material 20 uses a silicon base material as its material. By using a silicon substrate, the recess 22 and the hole 40 can be easily formed using a known photolithography method. In addition, the material which comprises the 2nd base material 20 is not specifically limited, If the formation of the recessed part 22 and the hole part 40 is possible and the joining performance with the 1st base material 10 is favorable, it will change suitably. You may do it.

  The planar shape (the shape seen from the Z-axis direction) of the first base material 10 and the second base material 20 is not particularly limited as long as the functional element 100 can be accommodated in the cavity 32. In the present embodiment, a rectangular shape is used as shown in FIG.

(Cavity 32)
The cavity 32 is provided with the functional element 100 and is sealed in a reduced pressure state or a state filled with an inert gas (for example, nitrogen gas).
For example, when the functional element 100 is used as a sensor for detecting angular velocity or the like, the cavity 32 is preferably in a reduced pressure state (more preferably in a vacuum state). Thereby, it can suppress that the vibration of the functional element 100 attenuate | damps by the viscosity of air.
When the functional element 100 is used as a sensor for detecting acceleration or the like, the cavity 32 is generally in an atmospheric pressure state, but is preferably in a state where it is replaced with an inert gas such as nitrogen. The cavity 32 is replaced with an inert gas, thereby suppressing oxidation of the functional element 100 and contributing to reliability.

(Sealing part 60)
The sealing part 60 is arrange | positioned so that the hole part 40 may be obstruct | occluded.
The sealing unit 60 can seal the cavity 32 by closing the hole 40. For example, gold / germanium (Au / Ge), gold / silicon (Au / Si), gold / tin (Au / Sn), tin / lead (Sn) An alloy such as Pb), lead / silver (Pb / Ag), tin / silver / copper (Sn / Ag / Cu), tin / zinc / bismuth (Sn / Zn / Bi) can be used. The sealing part 60 of the present embodiment uses an alloy containing gold / germanium (Au / Ge) in order to improve the adhesion to the metal film 50 described above.
The material of the sealing part 60 (sealing member 60B) is not particularly limited, and may be changed as appropriate as long as the material can block the hole 40 and ensure the airtightness of the cavity 32. Good. The sealing part 60 is preferably made of a material having a low melting point and is easily solidified. Since the melting point is low, deformation and damage of the functional element 100 to be sealed can be prevented, and the airtight performance of the cavity 32 can be improved. Moreover, the temperature rise of the 2nd base material 20 at the time of sealing can be suppressed, and it can suppress that the gas included in the 2nd base material 20 grade | etc., Releases | releases in the cavity 32. FIG.

(Structure of functional element 100)
The functional element 100 is provided on the first base material 10. The functional element 100 is accommodated in a cavity 32 formed by the first base material 10 and the second base material 20. The form of the functional element 100 is not particularly limited, and may be various forms such as an angular velocity (gyro) sensor, an acceleration sensor, a vibrator, a SAW (surface acoustic wave) element, a microactuator, and the like.

In the present embodiment, an electronic device 1 using the functional element 100 as an angular velocity sensor will be described.
FIG. 3 is a plan view schematically showing the functional element 100 according to the electronic device 1 of the present embodiment. 3 to 7, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other.

  As shown in FIG. 3, the functional element 100 includes a structure 104, a driving fixed electrode 130, a detecting fixed electrode 140, and a fixing unit 150.

  The structural body 104 is integrally provided by, for example, processing the silicon substrate 100a (see FIG. 8) bonded to the first base material 10. Accordingly, it is possible to apply a fine processing technique used for manufacturing a silicon semiconductor device, and the structure 104 can be downsized.

  The structural body 104 is supported by a fixing portion 150 (outer peripheral edge 103) fixed to the first base material 10 (see FIG. 1), and is disposed separately from the first base material 10. The structure body 104 includes a first vibrating body 106 and a second vibrating body 108. The first vibrating body 106 and the second vibrating body 108 are connected to each other along the X-axis direction.

  The first vibrating body 106 and the second vibrating body 108 have shapes that are symmetric with respect to the respective boundary lines B (straight lines along the Y-axis direction). In other words, the first vibrating body 106 and the second vibrating body 108 have the same configuration. Therefore, hereinafter, the configuration of the first vibrating body 106 will be described, and the description of the configuration of the second vibrating body 108 will be omitted.

  The first vibrating body 106 includes a drive unit 110 and a detection unit 120. The drive unit 110 includes a drive support unit 112, a drive spring unit 114, and a drive movable electrode 116.

  The driving support 112 has, for example, a rectangular (frame shape) shape, and the detection unit 120 is disposed inside the driving support 112. In the illustrated example, the driving support portion 112 includes a first extension portion 112a that extends along the X-axis direction and a second extension portion 112b that extends along the Y-axis direction. Yes.

  The drive spring portion 114 is disposed outside the drive support portion 112. In the illustrated example, one end of the driving spring portion 114 is connected to the vicinity of the corner portion of the driving support portion 112 (the connecting portion between the first extending portion 112a and the second extending portion 112b). The other end of the driving spring portion 114 is connected to the fixed portion 150.

  In the illustrated example, four driving spring portions 114 are provided in the first vibrating body 106. Therefore, the first vibrating body 106 is supported on the first base material 10 by the four fixing portions 150. Note that the fixing portion 150 on the boundary line B between the first vibrating body 106 and the second vibrating body 108 may not be provided.

  The drive spring portion 114 has a shape extending along the X-axis direction while reciprocating along the Y-axis direction. The plurality of driving spring portions 114 are imaginary lines (not shown) along the X-axis direction passing through the center of the driving support portion 112 and imaginary lines along the Y-axis direction passing through the center of the driving support portion 112. (Not shown) provided symmetrically. By making the drive spring portion 114 as described above, the drive spring portion 114 is prevented from being deformed in the Y-axis direction and the Z-axis direction, and the drive spring portion 114 is vibrated in the vibration direction of the drive portion 110. Can be smoothly expanded and contracted in the X-axis direction. As the driving spring portion 114 expands and contracts, the driving support portion 112 (the driving portion 110) can be vibrated along the X-axis direction. The number of the driving spring portions 114 is not particularly limited as long as the driving support portions 112 can vibrate along the X-axis direction.

  The drive movable electrode 116 is connected to the drive support portion 112 and disposed outside the drive support portion 112. More specifically, the driving movable electrode 116 is connected to the first extending portion 112 a of the driving support portion 112.

  The driving fixed electrode 130 is disposed outside the driving support portion 112. The driving fixed electrode 130 is fixed on the first base material 10 (see FIG. 1). In the example shown in the drawing, a plurality of driving fixed electrodes 130 are provided, and are arranged to face each other via the driving movable electrode 116. In the illustrated example, the driving fixed electrode 130 has a comb-like shape, and the driving movable electrode 116 has a protrusion 116 a that can be inserted between the comb teeth of the driving fixed electrode 130. Yes. By reducing the distance (gap) between the driving fixed electrode 130 and the protruding portion 116a, the electrostatic force acting between the driving fixed electrode 130 and the driving movable electrode 116 can be increased.

  When a voltage is applied to the driving fixed electrode 130 and the driving movable electrode 116, an electrostatic force can be generated between the driving fixed electrode 130 and the driving movable electrode 116. As a result, the drive spring portion 114 expands and contracts along the X-axis direction, and the drive support portion 112 (drive portion 110) can be vibrated along the X-axis direction.

  In the example shown in the figure, four drive movable electrodes 116 are provided in the first vibrating body 106, but if the drive support portion 112 can be vibrated along the X-axis direction, the number thereof is as follows. There is no particular limitation. In the illustrated example, the driving fixed electrode 130 is opposed to the driving movable electrode 116, but if the driving support 112 can be vibrated along the X-axis direction, the driving fixed electrode 130 is driven. The fixed electrode 130 may be disposed only on one side of the driving movable electrode 116.

  The detection unit 120 is connected to the drive unit 110. In the illustrated example, the detection unit 120 is disposed inside the drive support unit 112. The detection unit 120 can include a detection support unit 122, a detection spring unit 124, and a detection movable electrode 126. Although not shown, the detection unit 120 may be disposed outside the drive support unit 112 as long as it is connected to the drive unit 110.

  The detection support portion 122 has, for example, a rectangular (frame shape) shape. In the illustrated example, the detection support portion 122 includes a third extension portion 122a that extends along the X axis and a fourth extension portion 122b that extends along the Y axis.

  The detection spring portion 124 is disposed outside the detection support portion 122. The detection spring portion 124 connects the detection support portion 122 and the drive support portion 112. More specifically, one end of the detection spring part 124 is connected to the vicinity of a corner of the detection support part 122 (a connection part between the third extension part 122a and the fourth extension part 122b). The other end of the detection spring portion 124 is connected to the first extending portion 112 a of the drive support portion 112.

  The detection spring portion 124 has a shape extending along the Y-axis direction while reciprocating along the X-axis direction. In the illustrated example, four detection spring portions 124 are provided in the first vibrating body 106. The plurality of detection spring portions 124 are imaginary lines (not shown) along the X-axis direction passing through the center of the detection support portion 122 and imaginary lines along the Y-axis direction passing through the center of the detection support portion 122. (Not shown) provided symmetrically. By making the detection spring part 124 as described above, the detection spring part 124 is prevented from being deformed in the X-axis direction and the Z-axis direction, and the detection spring part 124 is vibrated by the vibration of the detection part 120. Can be smoothly expanded and contracted in the Y-axis direction. As the detection spring part 124 expands and contracts, the detection support part 122 (the detection part 120) can be vibrated along the Y-axis direction. The number of the detection spring portions 124 is not particularly limited as long as the detection support portion 122 can vibrate along the Y-axis direction.

  The detection movable electrode 126 is connected to the detection support portion 122 and arranged inside the detection support portion 122. In the example shown in the drawing, the detection movable electrode 126 extends along the X-axis direction and is connected to the two fourth extension portions 122 b of the detection support portion 122.

  The detection fixed electrode 140 is disposed inside the detection support part 122. The detection fixed electrode 140 is fixed on the first substrate 10 (see FIG. 1). In the example shown in the figure, a plurality of detection fixed electrodes 140 are provided, and are arranged to face each other via the detection movable electrode 126.

  The number and shape of the detection movable electrode 126 and the detection fixed electrode 140 are not particularly limited as long as a change in electrostatic capacitance between the detection movable electrode 126 and the detection fixed electrode 140 can be detected.

(Operation of functional element 100)
Next, the operation of the functional element 100 will be described. 4 to 7 are diagrams for explaining the operation of the functional element 100 in which the sealing structure according to the present embodiment is provided in the electronic device 1. For convenience, in FIGS. 4 to 7, each part of the functional element 100 is illustrated in a simplified manner.

  When a voltage is applied to the driving fixed electrode 130 and the driving movable electrode 116 by a driving circuit (not shown), an electrostatic force can be generated between the driving fixed electrode 130 and the driving movable electrode 116. As a result, as shown in FIGS. 4 and 5, the driving spring portion 114 can be expanded and contracted along the X-axis direction, and the driving portion 110 can be vibrated along the X-axis direction.

  More specifically, a first alternating voltage is applied between the driving movable electrode 116 and the driving fixed electrode 130 of the first vibrating body 106, and the driving movable electrode 116 and the driving fixed electrode of the second vibrating body 108 are fixed. A second alternating voltage that is 180 degrees out of phase with the first alternating voltage is applied between the electrodes 130. As a result, the first drive unit 110a of the first vibrating body 106 and the second drive unit 110b of the second vibrating body 108 can be vibrated along the X-axis direction at opposite phases and at a predetermined frequency. . That is, the first driving unit 110a and the second driving unit 110b connected to each other along the X-axis direction vibrate in the opposite phases along the X-axis direction (first vibration). For example, first, as shown in FIG. 4, the first drive unit 110a is displaced in the α1 direction, and the second drive unit 110b is displaced in the α2 direction opposite to the α1 direction. Next, as shown in FIG. 5, the first drive unit 110a is displaced in the α2 direction, and the second drive unit 110b is displaced in the α1 direction. The first driving unit 110a and the second driving unit 110b repeat this operation. In this way, the first drive unit 110a and the second drive unit 110b vibrate in mutually opposite phases.

  Since the detection unit 120 is connected to the drive unit 110, the detection unit 120 also vibrates along the X-axis direction with the vibration of the drive unit 110. That is, the first vibrating body 106 and the second vibrating body 108 vibrate in mutually opposite phases along the X axis.

  As shown in FIGS. 6 and 7, when an angular velocity ω around the Z axis is applied to the functional element 100 in a state where both of the driving units 110 a and 110 b are performing the first vibration, Coriolis force acts, and the detection unit 120 is displaced along the Y-axis direction. That is, the first detection unit 120a connected to the first drive unit 110a and the second detection unit 120b connected to the second drive unit 110b are mutually moved along the Y-axis direction by the first vibration and the Coriolis force. Displace in the opposite direction.

  For example, as shown in FIG. 6, the first detector 120a is displaced in the β1 direction, and the second detector 120b is displaced in the β2 direction opposite to the β1 direction. Further, as shown in FIG. 7, the first detection unit 120a is displaced in the β2 direction, and the second detection unit 120b is displaced in the β1 direction. The first detection unit 120a and the second detection unit 120b repeat this operation while receiving the Coriolis force.

  The distance L between the detection movable electrode 126 and the detection fixed electrode 140 changes when both the detection units 120a and 120b are displaced along the Y-axis direction. Therefore, the electrostatic capacitance between the detection movable electrode 126 and the detection fixed electrode 140 changes. In the functional element 100, by applying a voltage to the detection movable electrode 126 and the detection fixed electrode 140, the amount of change in capacitance between the detection movable electrode 126 and the detection fixed electrode 140 is detected, and Z An angular velocity ω around the axis can be obtained.

  In addition, although the form (electrostatic drive system) which drives the drive part 110 with an electrostatic force was demonstrated above, the method to drive the drive part 110 is not specifically limited, A piezoelectric drive system or the Lorentz force of a magnetic field is used. The electromagnetic drive system used can be applied.

(Method for manufacturing electronic device 1)
Next, a method for manufacturing the electronic device 1 according to the present embodiment will be described with reference to FIGS.

FIG. 8A shows a state in which the first base material 10 and the silicon substrate 100a to be the functional element 100 are joined (connected). In the first base material 10, the recess 12 and the metal plate 11 are formed on the main surface 10 a.
For example, the concave portion 12 is formed by coating a region of the first base material 10 to be the concave portion 12 with a metal thin film (not shown) (for example, chromium) and patterning the metal thin film using a photolithography technique. Using the patterned metal thin film as a mask, the first substrate 10 is wet etched with a chemical solution such as hydrofluoric acid. Moreover, the recessed part (not shown) of the area | region which forms the metal plate 11 can be formed simultaneously with the recessed part 12 mentioned above.
The metal plate 11 can be formed by, for example, applying a mask pattern in which a region (concave portion) formed by the metal plate 11 is opened and performing a sputtering method.

The silicon substrate 100 a is bonded to the top surface 12 a (main surface 10 a) of the first base material 10.
The first substrate 10 and the silicon substrate 100a can be joined using an anodic bonding method. The bonding between the first base material 10 and the silicon substrate 100a is not limited to the anodic bonding method, and a bonding method such as wafer direct bonding can be used. Alternatively, a metal eutectic bonding method may be used in which a metal thin film is provided on each of the surfaces where the first base material 10 and the silicon substrate 100a are bonded, and the metal thin films are eutectic bonded to each other.

FIG. 8B shows a state where the functional element 100 is formed by processing the silicon substrate 100 a bonded to the first base material 10.
For example, the functional element 100 is formed by thinning the silicon substrate 100a to a thickness necessary for the functional element 100 by grinding the silicon substrate 100a with a grinding apparatus. Next, a thin film (for example, a silicon oxide thin film) serving as a mask is formed on the thinned silicon substrate 100a, and patterning is performed using a known photolithography technique. Then, the functional element 100 is formed on the silicon substrate 100a by dry etching using the thin film pattern as a mask. As the dry etching method, the Bosch method in which an etching process and a deposition (deposition) process are repeated is used.

FIG. 8C shows a state in which the concave portion 22 and the hole 40 are formed in the second base material 20.
In the second base material 20, the recess 22, the hole 40, and the metal film 50 are formed.
The concave portion 22 can be formed, for example, by patterning a region of the second base material 20 to be the concave portion 22 by using a photolithography technique and etching the patterned second base material 20. In this example, the recess 22 was formed by a dry etching method. For example, the hole 40 is formed by patterning a region in which the hole 40 is formed on the main surface 20a side and the sub surface 20b side of the second base material 20 by a photolithography technique, so that the main surface 20a side and the sub surface are formed. An anisotropic wet etching method can be used from both sides with the 20b side. In this example, an aqueous potassium hydroxide solution (KOH) was used. In addition, the hole 40 is formed by immersing the second base material 20 in which the hole 40 is formed in hydrofluoric acid to form a curved surface (roundness) on the side 40 e of the hole 40. In this embodiment, the curved surface is formed on the side 40e by setting the mixing ratio of fluorinated acetic acid to HF: HNO3: CH3COOH = 13: 84: 3, and immersing the second substrate 20 in the fluorinated acetic acid for approximately 2 minutes. It was done by doing. By forming a curved surface (roundness) on the side 40e of the hole 40, it is possible to prevent a crack from being generated when the sealing member 60B is filled.
Further, the metal film 50 is formed on the second base material 20. For example, a sputtering method can be used to form the metal film 50. The metal film 50 of this embodiment can be formed by sputtering gold (Au) with titanium (Ti) as a base. In addition to titanium, a material such as chromium (Cr) or tungsten (W) may be used.

FIG. 9D shows a state where the first base material 10 and the second base material 20 are joined (connected).
The connection between the first base material 10 and the second base material 20 is performed by joining the top surface 12 a of the recess 12 and the top surface 22 a of the recess 22. The connection between the first substrate 10 and the second substrate 20 is a cavity constituted by the recess 12 and the recess 22 by connecting the bottom surface 12b of the recess 12 and the bottom surface 22b of the recess 22 to face each other. 32 can be provided. Further, the functional element 100 can be accommodated in the cavity 32.

  The joining of the first base material 10 and the second base material 20 can be performed using an anodic bonding method. The joining of the first base material 10 and the second base material 20 is not limited to the anodic joining method, and a joining method using an adhesive member such as a glass frit can be used. In addition, a metal eutectic contact in which a metal thin film is provided on each of the surfaces (the top surface 12a and the top surface 22a) to which the first base material 10 and the second base material 20 are bonded and the metal thin films are eutectic bonded to each other. Legal methods may be used. Thereby, while being able to improve the adhesiveness of the 1st base material 10 and the 2nd base material 20, the airtightness of the cavity 32 sealed by the sealing member 60B mentioned later can be improved.

FIG. 9E shows a state where the hole 40 is closed by the sealing portion 60 and the cavity 32 is sealed.
The hole 40 is closed by disposing the sealing member 60B in the hole 40 and melting the sealing member 60B. The shape of the sealing member 60B is not particularly limited, but a spherical shape is preferable. The sealing member 60B can be uniformly melted (melted) by having a spherical shape.
FIG. 9F is a process diagram for explaining the process from the joining process of the first base material 10 and the second base material 20 to the sealing process by the sealing member 60B. After joining the first base material 10 and the second base material 20, moisture and organic substances adhering in the cavity 32 are removed by a heat treatment process. For example, it is heated to a temperature of 200 [° C.] or higher and left for 1 hour or longer. You may carry out in inert gas atmosphere, such as a vacuum atmosphere and nitrogen gas, as needed. Thereafter, the sealing member 60B is disposed in the hole 40, and the atmosphere is decompressed (decompression process). In the present embodiment, since an angular velocity sensor is applied as the electronic device 1, the reduced-pressure atmosphere is set to 100 [Pa] or less. In addition, when an acceleration sensor is applied as the electronic device 1, for example, after removing unnecessary gas such as water vapor as a reduced pressure atmosphere up to about 3 [kPa], an inert gas such as nitrogen is introduced. Pressurize to atmospheric pressure (1013 [hPa]). This is because a general acceleration sensor uses a gas viscous resistance to design characteristics. Thereafter, the sealing member 60B is melted to close the hole 40 (sealing step). Details of the sealing step will be described below.
FIG. 10A and FIG. 10B show a state in which the sealing member 60B is disposed in the hole 40 and the laser light L is applied to the sealing member 60B.
To close the hole 40, the sealing member 60B is disposed so as to close the first opening 41 of the hole 40, and the arranged sealing member 60B is irradiated with the laser light L. The hole 40 is blocked by the sealing member 60B being heated and melted by the irradiated laser light L. Further, the cavity 32 sealed by closing the hole 40 is sealed in a reduced pressure state or filled with an inert gas according to the functional element 100 provided in the cavity 32. It is preferable. Therefore, the hole 40 is closed in a chamber maintained in a reduced pressure state or a state filled with an inert gas. When the hole 40 is closed in a reduced pressure state, the pressure is reduced to approximately 10 [Pa] or less. Further, when the hole 40 is closed in a state of being filled with an inert gas, the gas remaining in the cavity 32 is removed in advance under a reduced pressure atmosphere, and then the inert gas is replaced.

Here, the laser beam L is condensed so as to be focused on the sealing member 60B. The width W of the focused laser beam L is preferably narrower than the width of the sealing member 60B. In this embodiment, since the sealing member 60B having a spherical shape is used, the width of the sealing member 60B will be described as a diameter D in the following description.
When the width W of the laser beam L is larger than the diameter D of the sealing member 60B, the laser beam L may be applied to the inner wall 40a of the hole 40 and the second base material 20 may be heated. When the second base material 20 is heated, a gas (for example, a process gas such as argon (Ar) or nitrogen (N)) included in the second base material 20 may be released and released into the cavity 32. is there. For example, in the case of the cavity 32 that is sealed in a reduced pressure state, the pressure in the cavity 32 is reduced, which may affect the operation of the functional element 100. In addition, for example, in the case of the cavity 32 that is sealed in a state where it is filled with an inert gas, there is a possibility that the operation of the functional element 100 may be affected by a change in the gas composition in the cavity 32. Therefore, the width W of the laser light L is made smaller than the diameter D of the sealing member 60B, thereby suppressing that the laser light L is irradiated to the part other than the sealing member 60B and the irradiated part generates heat. it can.

The sealing member 60B solidifies along the inner wall 40a. More specifically, the sealing member 60B melts when irradiated with the laser beam L, and solidifies by being rapidly cooled by contacting the inner wall 40a of the hole 40. Solidification of the sealing member 60B occurs so as to rise toward the second opening 42 due to surface tension. At this time, the melted sealing member 60B is attracted by the inner wall 40a by the action of surface tension, and the thickness of the sealing portion 60 near the center of the first opening 41 is reduced.
Further, the heat generated when the melted sealing member 60B is solidified is absorbed by the second base material 20, and the temperature of the second base material 20 rises, leading to the temperature rise of the functional element 100. When the temperature of the functional element 100 rises, there is a risk that gas (for example, argon (Ar) or nitrogen (N)) used for forming the functional element 100 may be separated (deposited). There is a risk of being discharged into the cavity 32 and affecting the operation of the functional element 100 due to a decrease in the reduced pressure state in the cavity 32 or a change in the gas composition in the cavity 32.

Therefore, it is preferable to close the hole 40 by heating the second base material 20.
By heating the second substrate 20 and irradiating the laser beam L, the sealing member 60B is suppressed from solidifying along the inner wall 40a of the hole 40, and sealed as shown in FIG. The thickness of the portion 60 can be made uniform.

  In this embodiment, the hole 40 is blocked by using a spherical alloy having a diameter D of 250 [μm] and containing gold / germanium (Au / Ge) as the sealing member 60B. A sealing member 60B that is larger than the first opening 41 and smaller than the second opening 42 is used. Further, the energy of the laser light L irradiated to the sealing member 60B is 3.0 to 5.0 [J], and the width W of the laser light L irradiated to the sealing member 60B is approximately 30 [μm]. It was. In addition, the hole 40 was blocked by heating the second base material 20 to approximately 300 [° C.] and then irradiating the sealing member 60B with the laser light L to dissolve the sealing member 60B.

(Experiment with variable width W of laser beam L)
Here, the inventors conducted an experiment in which the sealing member 60B was melted by changing the width W of the laser light L applied to the sealing member 60B.
In this experiment, two electronic devices 1 (sample A and sample) in which a gyro sensor is formed as the functional element 100 and the cavity 32 is sealed by changing the width W of the laser light L applied to the sealing member 60B. B) was formed, and the shape and resonance characteristic Q value of the sealing portion 60 of the electronic device 1 were evaluated.

In the electronic device 1 to be evaluated, both the sample A and the sample B use the same shape as the first base material 10, the second base material 20, the functional element 100, and the sealing member 60B.
In sample A, the width W of the laser light L applied to the sealing member 60B is set to 300 [μm], which is larger than the diameter D of the sealing member 60B. Further, energy of 4.5 [J] (the output of the laser beam L was 0.15 [Kw] and the irradiation time of the laser beam L was 0.03 [Sec]) was applied to the sealing member 60B.
In the sample B, the width W of the laser light L applied to the sealing member 60B was set to 30 [μm], which is smaller than the diameter D of the sealing member 60B. Moreover, energy of 3.6 [J] (output 0.04 [Kw] of the laser beam L, irradiation time 0.09 [Sec] of the laser beam L) was given to the sealing member 60B.

FIG. 11A is a schematic diagram in which the cross section of the sealing portion 60 in the sample A and FIG. FIG. 12 is a graph summarizing the evaluation results of the resonance characteristic Q values related to the functional element 100 in Sample A and Sample B. In this embodiment in which an angular velocity sensor is applied as the electronic device 1, the resonance characteristics of the functional element 100 greatly affect the characteristics of the angular velocity sensor. Specifically, if the resonance characteristic Q value of the functional element 100 is large, it is advantageous for improving the performance of sensitivity and power consumption.
In the sample A, as shown in FIG. 11A, the sealing portion 60 was depressed at the central portion of the sealing portion 60. Further, the melted sealing member 60B rose to the vicinity of the second opening along the inner wall 40a of the hole 40 by the surface tension, and the sealing portion 60 was formed with a thickness that draws an arc. In sample A, the Q value was about 4500 as shown in FIG.
In the sample B, as shown in FIG. 11B, the sealing portion 60 is suppressed from rising of the molten sealing member 60B along the inner wall 40a of the hole 40, and has a substantially uniform thickness. 60 was formed. In Sample A, the Q value was about 15000 as shown in FIG.
Therefore, the experiment has shown that the resonance characteristic Q value indicating the performance of the electronic device 1 is improved by suppressing the detachment of the gas from the second base material 20 and the functional element 100. Therefore, the sensor characteristics such as sensitivity and power consumption are improved in the angular velocity sensor of this embodiment. On the other hand, when an acceleration sensor is applied as the electronic device 1, it is possible to provide a highly reliable device performance because a good airtight state can be maintained while removing unnecessary gases such as water vapor.

  The manufacture of the electronic device 1 of this embodiment is completed by closing the hole 40 and sealing the cavity 32.

According to the embodiment described above, the following effects can be obtained.
According to such an electronic device 1 and a method for manufacturing the electronic device 1, the spot width of the laser beam L (the diameter of the laser beam) irradiated to the sealing member 60 </ b> B that closes the hole 40 is the sealing member. By being narrower than the diameter D of 60B, it can suppress that the laser beam L is irradiated other than the sealing member 60B. Therefore, the first base material 10, the second base material 20, the functional element 100, and the hole 40 provided in the second base material 20 are suppressed from being irradiated with the laser light L. Further, it is possible to suppress the heat generated by the irradiation and the release of the gas contained in the first base material 10, the second base material 20, and the functional element 100 due to the heat generation and release into the cavity 32. it can. Therefore, it is possible to suppress changes in the pressure and gas composition in the cavity 32 and to influence the operation of the functional element 100 provided in the cavity 32.

(Example)
Examples to which the electronic device 1 according to the embodiment of the present invention is applied will be described with reference to FIGS. 13 to 16.

[Electronics]
An electronic apparatus to which the electronic device 1 according to the embodiment of the present invention is applied will be described with reference to FIGS.

  FIG. 13 is a perspective view schematically illustrating a configuration of a laptop (or mobile) personal computer as an electronic apparatus including the electronic device 1 according to the embodiment of the present invention. In this figure, a laptop personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 1008. The display unit 1106 has a hinge structure portion with respect to the main body portion 1104. It is supported so that rotation is possible. Such a laptop personal computer 1100 is equipped with an electronic device 1 that measures physical quantities such as acceleration and angular velocity for measuring the fall and inclination thereof. In such an electronic device 1, the airtightness of the cavity 32 in which the functional element 100 is provided is enhanced, and the detachment of gas from the first base material 10, the second base material 20, and the functional element 100 is suppressed. At the same time, the detection accuracy is improved. Therefore, by mounting the electronic device 1 described above, a laptop personal computer 1100 that can be downsized with high reliability can be obtained.

  FIG. 14 is a perspective view schematically illustrating a configuration of a mobile phone (including PHS) as an electronic apparatus including the electronic device 1 according to the embodiment of the invention. In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit 1208 is disposed between the operation buttons 1202 and the earpiece 1204. Such a cellular phone 1200 is equipped with the electronic device 1 that measures physical quantities such as acceleration and angular velocity for measuring the fall and inclination. In such an electronic device 1, the airtightness of the cavity 32 in which the functional element 100 is provided is enhanced, and the detachment of gas from the first base material 10, the second base material 20, and the functional element 100 is suppressed. At the same time, the detection accuracy is improved. Therefore, by mounting the electronic device 1 described above, a mobile phone 1200 that can be downsized with high reliability can be obtained.

FIG. 15 is a perspective view schematically illustrating a configuration of a digital still camera as an electronic apparatus including the electronic device 1 according to the embodiment of the present invention. In this figure, connection with an external device is also simply shown. Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an image sensor such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.
A display unit 1308 is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to perform display based on an imaging signal from the CCD. The display unit 1308 displays an object as an electronic image. Functions as a viewfinder. A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302.
When the photographer confirms the subject image displayed on the display unit 1308 and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1310. In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the drawing, a liquid crystal display 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory 1310 is output to the liquid crystal display 1430 or the personal computer 1440 by a predetermined operation. Such a digital still camera 1300 is equipped with an electronic device 1 that measures physical quantities such as acceleration and angular velocity for measuring the fall and inclination thereof. In such an electronic device 1, the airtightness of the cavity 32 in which the functional element 100 is provided is enhanced, and the detachment of gas from the first base material 10, the second base material 20, and the functional element 100 is suppressed. At the same time, the detection accuracy is improved.

  In addition to the laptop personal computer (mobile personal computer) shown in FIG. 13, the mobile phone shown in FIG. 14, and the digital still camera shown in FIG. , Smartphones, ink jet dispensing devices (eg ink jet printers), televisions, video cameras, video tape recorders, car navigation devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game machines, word processors, work Station, video phone, security TV monitor, electronic binoculars, POS terminal, medical equipment (eg electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish detector, various measurements Equipment, instruments (eg, vehicles Aircraft, gauges of a ship), can be applied to electronic equipment such as a flight simulator.

[Moving object]
FIG. 16 is a perspective view schematically showing an automobile as an example of a moving body. The automobile 1500 is equipped with various control units including the electronic device 1 that processes various control signals. For example, as shown in the figure, an automobile 1500 as a moving body includes an electronic control unit (ECU) 1508 that incorporates a sensor that detects the acceleration of the automobile 1500 and controls the output of the engine. 1507. The electronic control unit 1508 is equipped with the electronic device 1 that measures physical quantities such as acceleration and angular velocity of the vehicle body 1507. In such an electronic device 1, the airtightness of the cavity 32 in which the functional element 100 is provided is enhanced, and the detachment of gas from the first base material 10, the second base material 20, and the functional element 100 is suppressed. At the same time, the detection accuracy is improved. Therefore, it is possible to obtain an automobile 1500 as an efficient moving body that performs appropriate engine output control according to the posture of the vehicle body 1507 with high accuracy and suppresses consumption of fuel and the like.
In addition, the electronic device 1 can be widely applied to a vehicle body attitude control unit, an anti-lock brake system (ABS), an air bag, a tire pressure monitoring system (TPMS), and the like.

  DESCRIPTION OF SYMBOLS 1 ... Electronic device, 10 ... 1st base material, 10a ... Main surface, 11 ... Metal plate, 12 ... Recessed part, 12a ... Top surface, 12b ... Bottom surface, 20 ... 2nd base material, 20a ... Main surface, 20b ... Secondary Surface, 22 ... concave portion, 22a ... top surface, 22b ... bottom surface, 32 ... cavity, 40 ... hole, 40a ... inner wall, 40e ... side, 41 ... first opening, 42 ... second opening, 50 ... metal film, DESCRIPTION OF SYMBOLS 60 ... Sealing part, 60B ... Sealing member, 100 ... Functional element, 100a ... Silicon substrate, 103 ... Outer periphery, 1100 ... Laptop personal computer, 1200 ... Mobile phone, 1300 ... Digital still camera, 1500 ... Automobile.

Claims (3)

A first substrate;
A second substrate;
A cavity that is surrounded by the first substrate and the second substrate,
A sealing portion provided in the second base material and disposed in a hole portion penetrating the cavity;
A functional element provided in the cavity, and a method of manufacturing an electronic device comprising:
Heating the second base material, irradiating the sealing member disposed in the hole with a laser beam to melt the sealing member to close the hole ,
The method of manufacturing an electronic device, wherein a spot width of the laser beam is narrower than a width of the sealing member when the hole is viewed in plan. The hole has a first opening having an opening on the cavity side and a second opening having an opening on the side opposite to the cavity, and the hole is viewed in plan view. In this case, the hole is closed by irradiating the laser beam to the sealing member that is wider than the first opening and narrower than the second opening to melt the sealing member. The method for manufacturing an electronic device according to claim 1 . Wherein before the step of melting the sealing member, a method for fabricating an electronic device according to claim 1 or claim 2, characterized in that it comprises a step of depressurizing the cavity.

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